Islet Cell Transplantation

Islet Cell Transplantation: Type 1 diabetes is a very serious disorder that impacts the day to day existence of the people that suffer from it. While there are many effective treatment options for type 1 diabetes there is still no cure. While there are several potential technologies on the horizon that promise to lessen or even eliminate the worst effects of the disease, such as the closed loop insulin pump (sometimes inaccurately called an artificial pancreas) and pancreas transfers, the technology that holds the most promise is the islet cell transplant.

The Islets of Langerhans are microscopic bodies in the pancreas that are responsible for creating and secreting a number of important enzymes, the most well known of which is insulin. These bodies are what fail in a diabetic. In type 2 diabetes, they may produce insulin in smaller amounts than what are necessary (this is not always true–there are also other causes of type 2 diabetes) and they fail altogether in the much more serious type 1 diabetes. Type 1 diabetics must monitor their blood glucose levels many times and day and add insulin as needed, typically through injections or an insulin pump.

There are several types of cells in the Islets of Langerhans. The beta cells are responsible for the production of insulin. The hope for Islet cell transplant is that the beta cells from the donor will become active in the recipient’s pancreas and begin to produce and secrete insulin in the new host. This technique has been successful in limited testing–if it can be refined and made available to a much wider audience, it will be the elusive cure for diabetes that have been sought for years. While testing is in its very early stages, some of the published results have been promising indeed. Many of the recipients have gone for a year or more without having to take a single supplemental dose of insulin. The tests are underway and hopefully the future will hold many more such promising results.

One of the real hurdles that must be overcome before islet cell transplants can be made a viable option for many sufferers of type 1 diabetes is the problem of rejection. Every cell in a human body is covered with unique markers that indicate that the cell is native to the body and not an outside pathogen. Cells that do not contain these individual specific markers are attacked by the immune system which treats them as invaders. With any kind of transplant, the problem of rejection is a very real issue. Since the transplanted cells will have different markers, the immune system will attempt to destroy them since they appear to be outsiders (indeed, they are). The only way to currently prevent rejection is to use medications that decrease the activity of the immune system. This clearly has drawbacks. First, we need our immune systems function properly to keep us health. Those who have a decreased immune system are likely to suffer from a wide range of problems, including frequent cold and flu infections, a high occurrence of mouth and stomach ulcers, higher rates of general infections, etc. The complications that accompany rejection suppression will mean that islet transplant surgery will only be appropriate for those whose diabetes symptoms are worse than the side effects that they will incur because of the required immunosuppressive therapy.

Another problem with the current state of islet transplants is that there simply are not enough donors available to meet the needs of even a small percentage of all type 1 diabetics. Since there will surely be overwhelming demand for the procedure once some of the details are worked out, scientists are currently investigating ways to artificially produce functional islet cells.